1. Field of Invention
The present invention relates to tags or locks for electrical equipment, particularly circuit breakers.
2. Description of Prior Art
In servicing or working on electrical lines or power equipment, safety considerations normally dictate that live electrical power be disconnected. Typically, this is done by interrupting the electrical circuit at a circuit breaker switch. Often, the work location may be out of view or at some distance from the circuit breaker. A risk was thus presented that someone unaware that service was in progress might inadvertently reset the circuit breaker switch. Restoration of electrical power in this manner was clearly a safety hazard.
It has been proposed to provide some mechanism so that a lock could be secured to the circuit breaker to prevent movement of the circuit breaker switch from an open or off position. U.S. Pat. Nos. 3,595,040 and 4,733,029 are examples of such an approach. However, the handle lock attachments of this type were fixedly attached by securing screws or rivets to the circuit breaker housing. This necessitated that openings for the securing members be formed, such as by drilling or tapping, in the body of the circuit breaker.
U.S. Pat. No. 3,291,924 related to structure which relied on a camming action of a lock attachment mechanism against the circuit breaker switch or handle. Forces exerted by this camming action urged the relatively yieldable synthetic resin material of the circuit breaker handle into a sharp biting metal edge or barb. Service usage would thus damage the circuit breaker handle.